Through the use of digital signals which are being transmitted at ever increasing frequencies, it is possible to transmit increasingly larger and more complex messages to remote portable units. Portable communications transceivers and other portable electronic equipment, such as cellular and cordless telephones, pagers, data banks, and the like, are becoming increasingly popular. In some instances it is possible to send complete messages, including alpha-numerics and/or graphics by way of novel pagers. Thus, complete messages can be sent to specific recipients by way of a pager, for example.
Also, in many instances it is desirable to provide a visual display on the communication transceiver to supply the operator with an indication of messages received, numbers actually dialed, and other minor but critical information. The problem is that the visual displays on prior art communications receivers are extremely limited in size and require relatively high electrical power as well as a great amount of area to be sufficiently large to produce a useful display. Thus, while the present visual displays are generally sufficient for displaying the minor information, they are not capable of displaying large alpha-numeric and/or graphic messages.
In the prior art, for example, it is common to provide visual displays utilizing liquid crystal displays, directly viewed light emitting diodes, etc. These produce very large and cumbersome displays that greatly increase the size of the transceiver and require relatively large amounts of power. Further, such displays, when used on pagers, greatly limit the amount and, in many instances, the type of messages that can be received.
Some types of devices have been proposed which are capable of displaying larger messages while utilizing a smaller amount of space in the portable electronic device. In one instance, the prior art includes a scanning mirror to produce a visual display but again this requires relatively large amounts of power and is very complicated and sensitive to shock. Also, the scanning mirror causes vibration in the unit that substantially reduces visual comfort and acceptability.
Some attempts have been made to produce displays using arrays of light emitting devices on a single semiconductor chip. Generally, a semiconductor chip, or integrated circuit, is mounted on a printed circuit board or the like and the accepted method for connecting the chip to external circuits is to use standard wire bond technology. However, when a semiconductor chip having a relatively large array of electrical components or devices formed thereon is to be connected, standard wire bond techniques can become very difficult. For example, if a relatively large array (greater than, for example, 10,000 or 100.times.100) of light emitting devices is formed on a semiconductor chip with a pitch (center-to-center separation) of P, then bond pads on the perimeter of the semiconductor chip will have a 2P pitch. This is true because every other row and every other column goes to an opposite edge of the perimeter to increase the distance between bond pads as much as possible.
At the present time wire bond interconnects from bond pads having a pitch of 4.8 milli-inches is the best that is feasible. Thus, in the array mentioned above of 100.times.100 light emitting diodes the bond pads on the perimeter of the semiconductor chip would have a minimum pitch of 4.8 milli-inches, with 50 bond pads situated along each edge of the perimeter. As more devices are included in the array, more bond pads are required and the perimeter size to accommodate the additional bond pads increases at an even greater rate. That is, since the minimum pitch of the bond pads is 4.8 milli-inches, the pitch of the devices in the array can be as large as 2.4 milli-inches, or approximately 61 microns, without effecting the size of the chip. Thus, even if the devices can be fabricated smaller than 61 microns, the minimum pitch of the bonding pads will not allow the perimeter of the chip to be made any smaller. It can quickly be seen that the size of the semiconductor chip is severely limited by the limitations of the wire bonding technology.
Further, it has been common practice to mount semiconductor chips and interface circuitry on a single board. The problem that arises is the large amount of surface area required to mount and connect various components.
Thus, there is a need for improved image manifestation apparatus and interconnect and packaging structures and techniques which can substantially reduce limitations on the size of the image manifestation apparatus and the semiconductor chips used therein,.
Accordingly, it is a purpose of the present invention to provide new and improved dual image manifestation apparatus with an integrated electro-optic package.
It is another purpose of the present invention to provide a new and improved dual image manifestation apparatus with an integrated electro-optic package including a direct view display and a large virtual display.
It is a further purpose of the present invention to provide a new and improved dual image manifestation apparatus with an integrated electro-optic package including a direct view display and a large virtual display which is compactly packaged.
It is yet another purpose of the present invention to provide a new and improved dual image manifestation apparatus with an integrated electro-optic package including a direct view display and a large virtual display which is relatively easy and inexpensive to fabricate.
It is still another purpose of the present invention to provide new and improved dual image manifestation apparatus including a direct view display and a large virtual display which is fabricated in a single integrated electro-optic package which can be easily incorporated into portable electronic equipment.
It is another purpose of the present invention to provide new and improved communication transceivers with dual image manifestation apparatus including a direct view display and a large virtual display.